Mother's Always Know! John invited his mother over for dinner.

Mother's Always Know!
John invited his mother over for dinner. During the meal, his mother
couldn't help noticing how beautiful John's roommate was. She had long been
suspicious of a relationship between John and his roommate and this only
made her more curious. Over the course of the evening, while watching the
two interact, she started to wonder if there was more between John and the
roommate than met the eye. Reading his mom's thoughts, John volunteered, "I
know what you must be thinking, but I assure you, Julie and I are just
roommates."
About a week later, Julie came to John and said, "Ever since your mother
came to dinner, I've been unable to find the beautiful silver gravy ladle.
"You don't suppose she took it, do you?" Julie said, "Well, I doubt it, but
I'll write her a letter just to be sure."
So he sat down and wrote: "Dear Mother, I'm not saying you 'did' take a
gravy ladle from my house, and I'm not saying you 'did not' take a gravy
ladle. But the fact remains that one has been missing ever since you were
here for dinner."
Several days later, John received a letter from his mother which read: "Dear
Son, I'm not saying that you 'do' sleep with Julie, and I'm not saying that
you 'do not' sleep with Julie. But the fact remains that if she was sleeping
in her own bed, she would have found the gravy ladle by now. Love, Mom"